Messenger RNA has been isolated from HeLa cells and used to direct the cell-free translation of hCG-alpha subunit. Glycosylation of hCG subunits in choriocarcinoma cells has been studied by the incorporation of labeled carbohydrates combined with gel filtration of oligosaccharides obtained by pronase digestion. The combining properties of exoglycosidase-treated and ectopic hCG subunits have been studied in cell-free combination assays.